This invention relates to halo-substituted methane-and chloromethane-sulfonanilides substituted in the para position by alkylthio, alkylsulfinyl or alkylsulfonyl groups and optionally substituted by trifluoromethyl and to agriculturally acceptable salts thereof. The compounds of the invention are active plant growth modifying agents. The invention also relates to plant growth modifying compositions comprising the compounds of the invention dispersed in agriculturally acceptable extending media and to the use of the compounds to modify the growth of higher plants. Methods for preparing the compounds and intermediates in their preparation are also included.
Plant growth modification as defined herein consists of all deviations from natural development, for example, defoliation, stimulation, stunting, inhibition, desiccation, tillering, and even death. This plant growth modifying activity is generally observed as the compounds of the invention begin to interfere with certain processes within the plant. If vital processes are affected, the plant will die if treated with a sufficient dose of the compound and the compound can be termed a herbicide relative to that plant. If the plant is a weed, the compound can be used to control or kill it and this is particularly valuable when a compound controls or kills a weed at an application rate that has little or no effect on a crop plant. I.e., it can serve as a selective herbicide to control or kill the weed in the presence of that crop. On the other hand, the growth of desirable plants can sometimes be modified beneficially, e.g., to suppress undesirable growth or to improve the quantity or quality of the harvest from the plant or to serve as a harvest aid. Such beneficial modifications can be termed plant growth regulation.
The compounds of the present invention are broadly active as plant growth modifiers. As such they are plant growth regulators and herbicides and frequently also serve as selective herbicides. The invention is particularly useful in the selective herbicide area to control particular weed species in the presence of specific crops (with little or no damage to the crops), for example to control such weeds as rhizomatous johnsongrass, annual grasses, yellow nutsedge and/or purple nutsedge in such crops as cotton, soybeans and corn.